parsing a xml file with c#

Question

I don't understand why I am getting errors when parsing an xml file. I have a class:

class FileSignature
{
    public string signature{ get; set; }
    public string[] extensions{ get; set; }
    public string description { get; set; }
}

I basically need to populate a list of FileSignature List<FileSignature> by parsing an xml file: the xml file looks like:

<?xml version="1.0" encoding="utf-8" ?>

<Files>
  <File>
    <Signature>482B424544562050726F6475637473204C6963656E7365204B65792046696C650000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001A</Signature>
    <Extension>KEY</Extension>
    <Description>AviraProductKey</Description>
  </File>
  <File>
    <Signature>FFFE570069006E0064006F0077007300200052006500670069007300740072007900200045006400690074006F0072002000560065007200730069006F006E00200035002E0030003000</Signature>
    <Extension>REG</Extension>
    <Description>RegistryDataFile5.00</Description>
  </File>
  <File>
    <Signature>41565020416E7469766972616C2044617461626173652E202863294B6173706572736B79204C616220313939372D32</Signature>
    <Extension>AVC</Extension>
    <Description>KasperskyAnti-VirusDatabase</Description>
  </File>
  <File>
    <Signature>00000002FFFFFFFFFFFFFFFF0000000000000000000000000000000000000000000000000000000000000000000000</Signature>
    <Extension>MAC</Extension>
    <Description>MacPaintBitmapGraphic</Description>
  </File>      
  <File>
    <Signature>52494646????????415649204C495354</Signature>
    <Extension>AVI</Extension>
    <Description>WindowsAudioVideoInterleave</Description>
  </File>      
  <File>
    <Signature>464C5601</Signature>
    <Extension>FLV</Extension>
    <Description>FlashVideo</Description>
  </File>
  <File>
    <Signature>1</Signature>
    <Extension>MPG</Extension>
    <Description>MPEGVideoFile</Description>
  </File>
  <File>
    <Signature>465753</Signature>
    <Extension>SWF</Extension>
    <Description>MacromediaFlashFormat</Description>
  </File>
  <File>
    <Signature>435753</Signature>
    <Extension>SWF</Extension>
    <Description>ShockwaveFlash(v5+)</Description>
  </File>
  <File>
    <Signature>FFD8FF</Signature>
    <Extension>JPG</Extension>
    <Description>JPEG/JIFFImage</Description>
  </File>
  <File>
    <Signature>1F8B08</Signature>
    <Extension>GZ</Extension>
    <Description>GZipCompressedArchive</Description>
  </File>
  <File>
    <Signature>1F9D90</Signature>
    <Extension>Z</Extension>
    <Description>UNIXCompressedArchive</Description>
  </File>
  <File>
    <Signature>494433</Signature>
    <Extension>MP3</Extension>
    <Description>MP3Audio</Description>
  </File>
  <File>
    <Signature>FFFB</Signature>
    <Extension>MP3</Extension>
    <Description>MP3Audio</Description>
  </File>
  <File>
    <Signature>FFFA</Signature>
    <Extension>MP3</Extension>
    <Description>MP3Audio</Description>
  </File>
  <File>
    <Signature>4D5A</Signature>
    <Extension>EXE|COM|DLL|SYS</Extension>
    <Description>WindowsExecutable</Description>
  </File>
  <File>
    <Signature>424D</Signature>
    <Extension>BMP</Extension>
    <Description>WindowsOS/2BitmapGraphics</Description>
  </File>
  <File>
    <Signature>9501</Signature>
    <Extension>SKR</Extension>
    <Description>PGPPrivateKeyring</Description>
  </File>
  <File>
    <Signature>9901</Signature>
    <Extension>PKR</Extension>
    <Description>PGPPublicKeyring</Description>
  </File>

</Files>

and I don't understand why my code is not working. I don't want the xml file to be in exact order. In other words I want to treat:

  <File>
    <Signature>4D5A</Signature>
    <Extension>EXE|COM|DLL|SYS</Extension>
    <Description>WindowsExecutable</Description>
  </File>

just like:

 <File>
    <Description>WindowsExecutable</Description>        
    <Extension>EXE|COM|DLL|SYS</Extension>
    <Signature>4D5A</Signature>
  </File>

and my code for parsing that xml file is:

class FileSignature
{
    public string signature;
    public string[] extensions;
    public string description { get; set; }
}

// Constructor here is where I start implementing the algorithm
class FileSignatures
{
    public static List<FileSignature> Files;

    public FileSignatures()
    {
        // list where to place the files
        Files = new List<FileSignature>();


        // that is the path where the xml is located
        XmlTextReader reader = new XmlTextReader(@"A:\Users\Tono\Desktop\SaveContentFromCache\SaveContentFromCache\FileSignatures.xml");


        while (reader.Read())
        {
            // if we find a file element then
            if (reader.Name.ToString().ToLower().Equals("file"))
            {
                // place that entire xml in a string
                string temp = reader.ReadInnerXml().ToString();

                // Create an XmlReader
                XmlReader readerOfParent = XmlReader.Create(new StringReader(temp));

                FileSignature f = new FileSignature();
                while (readerOfParent.Read()) // !!!!!!!!!!!! here is where I get the error 
                {
                    if (readerOfParent.Name.ToString().ToLower().Contains("signature"))
                        f.signature = readerOfParent.ReadInnerXml().ToString();

                    if (readerOfParent.Name.ToString().ToLower().Contains("extension"))
                        f.extensions = readerOfParent.ReadInnerXml().ToString().Split('|');

                    if (readerOfParent.Name.ToString().ToLower().Contains("description"))
                        f.description = readerOfParent.ReadInnerXml().ToString();
                }

                Files.Add(f);
                readerOfParent.Close();


            }

        }
    }

}

EDIT

Reading my algorithm might look confusing. I just need to place the content from the xml file into c#

Which version of .NET are you using?

John Saunders
– John Saunders

2011-11-05 05:09:30 +00:00
Commented Nov 5, 2011 at 5:09 — John Saunders
– John Saunders, Commented Nov 5, 2011 at 5:09

Damith · Accepted Answer · 2011-11-05 05:10:19Z

2

XDocument xdoc= XDocument.Load(@"A:\Users\Tono\Desktop\SaveContentFromCache\SaveContentFromCache\FileSignatures.xml");

List<FileSignature> fileSignatures = (from file in xdoc.Element("Files").Elements("File")
         select new FileSignature
         {
           signature= file.Element("Signature").Value,
           extensions= file.Element("Extension").Value.Split('|'),
           description = file.Element("Description").Value
         }).ToList();

edited Nov 5, 2011 at 5:10

answered Nov 5, 2011 at 4:53

Damith

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2 Comments

Tono Nam Over a year ago

I am not able to use xdoc.Element I am instantiating xdoc from System.Xml.Linq.XDocument . Maybe I need to add a reference to my wpf application. Thanks a lot for the help. If I new I could use linq I would have give it another try

Damith Over a year ago

@TonoNam try now. it should be Elements. i tested with your xml file and this is working fine.

John Saunders · Accepted Answer · 2011-11-05 05:09:55Z

I was working in a solution meanwhile waiting for an answer. I guess I should had tried longer. anyways here is what I worked out:

// list where to place the files
Files = new List<FileSignature>();

//Load xml
XDocument xdoc = XDocument.Load(@"A:\Users\Tono\Desktop\SaveContentFromCache\SaveContentFromCache\FileSignatures.xml");

//Run query
var files = from elements in xdoc.Descendants("File")
           select new { 
               Children = elements.Descendants()
           };

//Loop through results
foreach (var elem in files)
{
    FileSignature f = new FileSignature();
    foreach (var lv2 in elem.Children)
    {
        if (lv2.Name.ToString().ToUpper().Contains("SIGNATURE"))
            f.signature = lv2.Value.ToString();
        else if (lv2.Name.ToString().ToUpper().Contains("DESCRIPTION"))
            f.description = lv2.Value.ToString();
        else if (lv2.Name.ToString().ToUpper().Contains("EXTENSION"))
            f.extensions = lv2.Value.ToString().Split('|');              
    }
    Files.Add(f);
}

edit

UnhandledExeption solution looks much more simpler!

Merlyn Morgan-Graham · Accepted Answer · 2011-11-05 05:28:50Z

I worked on a different solution using XML serialization. It isn't quite as clean for a one-off reading as the Linq to XML example. But it will work in older code, and will be more easily embedded if you have more XML or a bigger object tree than just this list. It also supports both read and write operations.

using System.Collections.Generic;
using System.IO;
using System.Xml.Serialization;

public class FileSignature
{
    public override string ToString()
    {
        return string.Format("Description: '{0}', Extensions: '{1}', Signature: '{2}'"
            , Description
            , string.Join("|", (Extensions ?? new string[0]))
            , Signature
            );
    }

    public string Signature { get; set; }

    [XmlIgnore]
    public string[] Extensions { get; set; }

    [XmlElement(ElementName="Extension")]
    [System.ComponentModel.EditorBrowsable(
        System.ComponentModel.EditorBrowsableState.Never)]
    public string ExtensionsSerialized
    {
        get
        {
            return Extensions == null
                ? ""
                : string.Join("|", Extensions);
        }
        set
        {
            System.Console.WriteLine("Value: {0}", value);
            Extensions = value.Split('|');
        }
    }

    public string Description { get; set; }
}

[XmlRoot("Files")]
public class FileSignatureCollection
{
    public FileSignatureCollection()
    {
        Items = new List<FileSignature>();
    }

    [XmlElement("File")]
    public List<FileSignature> Items { get; set; }
}

class Program
{
    static void Main()
    {
        using(var xml = File.OpenRead("test.xml"))
        {
            var serializer = new XmlSerializer(typeof(FileSignatureCollection));
            var signatures = (FileSignatureCollection)serializer.Deserialize(xml);

            foreach(var sig in signatures.Items)
            {
                System.Console.WriteLine(sig);
            }
        }
    }
}

If this list is embedded in a bigger type, than you can forego the FileSignatureCollection wrapper.

Icarus · Accepted Answer · 2011-11-05 05:53:27Z

string xml = @"<?xml version=""1.0"" encoding=""utf-8"" ?><Files>  <File>    <Signature>482B424544562050726F6475637473204C6963656E7365204B65792046696C650000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001A</Signature>    <Extension>KEY</Extension>    <Description>AviraProductKey</Description>  </File>  <File>    <Signature>FFFE570069006E0064006F0077007300200052006500670069007300740072007900200045006400690074006F0072002000560065007200730069006F006E00200035002E0030003000</Signature>    <Extension>REG</Extension>    <Description>RegistryDataFile5.00</Description>  </File>  <File>    <Signature>41565020416E7469766972616C2044617461626173652E202863294B6173706572736B79204C616220313939372D32</Signature>    <Extension>AVC</Extension>    <Description>KasperskyAnti-VirusDatabase</Description>  </File>  <File>    <Signature>00000002FFFFFFFFFFFFFFFF0000000000000000000000000000000000000000000000000000000000000000000000</Signature>    <Extension>MAC</Extension>    <Description>MacPaintBitmapGraphic</Description>  </File>        <File>    <Signature>52494646????????415649204C495354</Signature>    <Extension>AVI</Extension>    <Description>WindowsAudioVideoInterleave</Description>  </File>        <File>    <Signature>464C5601</Signature>    <Extension>FLV</Extension>    <Description>FlashVideo</Description>  </File>  <File>    <Signature>1</Signature>    <Extension>MPG</Extension>    <Description>MPEGVideoFile</Description>  </File>  <File>    <Signature>465753</Signature>    <Extension>SWF</Extension>    <Description>MacromediaFlashFormat</Description>  </File>  <File>    <Signature>435753</Signature>    <Extension>SWF</Extension>    <Description>ShockwaveFlash(v5+)</Description>  </File>  <File>    <Signature>FFD8FF</Signature>    <Extension>JPG</Extension>    <Description>JPEG/JIFFImage</Description>  </File>  <File>    <Signature>1F8B08</Signature>    <Extension>GZ</Extension>    <Description>GZipCompressedArchive</Description>  </File>  <File>    <Signature>1F9D90</Signature>    <Extension>Z</Extension>    <Description>UNIXCompressedArchive</Description>  </File>  <File>    <Signature>494433</Signature>    <Extension>MP3</Extension>    <Description>MP3Audio</Description>  </File>  <File>    <Signature>FFFB</Signature>    <Extension>MP3</Extension>    <Description>MP3Audio</Description>  </File>  <File>    <Signature>FFFA</Signature>    <Extension>MP3</Extension>    <Description>MP3Audio</Description>  </File>  <File>    <Signature>4D5A</Signature>    <Extension>EXE|COM|DLL|SYS</Extension>    <Description>WindowsExecutable</Description>  </File>  <File>    <Signature>424D</Signature>    <Extension>BMP</Extension>    <Description>WindowsOS/2BitmapGraphics</Description>  </File>  <File>    <Signature>9501</Signature>    <Extension>SKR</Extension>    <Description>PGPPrivateKeyring</Description>  </File>  <File>    <Signature>9901</Signature>    <Extension>PKR</Extension>    <Description>PGPPublicKeyring</Description>  </File></Files>";

 XDocument doc = XDocument.Parse(xml);
 List<FileSignature> files = (
                     from c in doc.Descendants("File")
                     select new FileSignature 
                     { description=c.Descendants("Description").First().Value,
                       extensions =c.Descendants("Extension").First().Value.Split('|')  ,
                       signature=c.Descendants("Signature").First().Value }
                      ).ToList();

Will convert your XML string to a List<FileSignature>();

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parsing a xml file with c#

and my code for parsing that xml file is:

EDIT

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and my code for parsing that xml file is:

EDIT

4 Answers 4

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